Azido(η5-pentamethylcyclopentadienyl)[2-(pyridin-2-yl)phenyl]iridium(III)

In the title compound, [Ir(C10H15)(C11H8N)(N3)], the IrIII ion is coordinated by three anionic ligands, namely, pentamethylcyclopentadienyl (Cp*−), 2-(pyridin-2-yl)phenyl (ppy−) and azide (N3 −), and adopts a three-legged piano-stool geometry The coordination mode of N3 − is typical for Cp*IrIII–N3 complexes, with an Ir—N(N3) bond length of 2.125 (2) Å and an Ir—N=N bond angle of 116.5 (2)°. The N3 − ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy− ligand, the Ir—C and Ir—N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related IrIII– or RhIII–ppy complexes. The Ir—C(Cp*) bond lengths vary in the range 2.163 (2)–2.232 (2) Å, indicating a strong trans influence of the cyclometallated C-donor atom of the ppy− ligand.


Comment
In previous studies we have prepared a number of iridium(III) azido complexes, [Cp*Ir III (N 3 )(L-L′)] (Cp* = pentamethylcyclopentadienyl, L-L′ = various kinds of bidentate chelate ligands), and investigated their structures and photochemical reactivities. Among them, complexes of [Cp*Ir(N 3 )(Me 2 dtc)] (Me 2 dtc -= N,N-dimethyldithiocarbamate) and [Cp*Ir(N 3 )(2-Spy)] (2-Spy -= 2-pyridinethiolate) afforded interesting photolysis products with two-legged piano-stool structures, [Cp*Ir{SC(NMe 2 )SN}] and [Cp*Ir(1-N-2Spy)], respectively, by insertion of a N-atom originating from the coordinated azido ligand, into the Ir-S and Ir-N(py) bonds, respectively (Sekioka et al., 2005). In contrast, photolysis of the related complexes with an N-N, N-P or P-P type four-membered chelate ligand (i.e., 1,8-naphthyridine, 2-diphenylphosphinopyridine or bis(dimethylphosphino)methane) gave a complicated mixture of uncharacterized products, due probably to reductive elimination of the coordinated azide (Suzuki et al., 2009). In the case of [Cp*Ir(N 3 )(bpy)]PF 6 (bpy = 2,2′-bipyridine), photolysis in acetonitrile produced a 5-methyltetrazolato complex, [Cp*Ir(N 3 )(MeCN 4 )] + , which was confirmed by 1 H NMR spectroscopy (Kotera et al., 2008). In addition, the X-ray structural analysis of the bpy complex, The title compound crystallized in a monoclinic space group P2 1 /n with Z = 4. The Ir III ion was coordinated by three anionic ligands, Cp* -, ppyand N 3 -, and it took a three-legged piano-stool structure. The ppyligand formed a planar chelate, having the Ir1-C11 bond of 2.066 (2) Å and the Ir1-N22 bond of 2.079 (2) Å. It is noted that the difference between the Ir-C and Ir-N bond lengths is not so large (0.013 Å), compared to the typical Ir III or Rh III (M III )-ppy complexes, where the M-C bond is significantly shorter than the M-N bond (Takayama et al., 2013). In some cases of Ir III -ppy complexes with a simple halide, similarly small differences in the Ir-C and Ir-N bonds were also reported; for These small differences may be due to a partial configurational disorder of the ppy coordination. The five Ir1-Cn(Cp*) bond lengths are 2.175 (2), 2.163 (2), 2.201 (2), 2.230 (2) and 2.232 (2) Å for n = 1-5, respectively (Table 1). Two relatively long (to C4 and C5) bonds are approximately trans to the C-donor atom of ppyligand. A similar elongation of the Ir-C bonds are also observed in the other mononuclear [Cp*Ir III (ppy)X] complexes (Park-Gehrke et al., 2009;Takayama et al., 2013), indicating a strong trans influence of the cyclometalated C-donor. The Ir1-C3 bond, which is trans to the N-donor of ppy -, is a little longer than the other two; this may indicate a partial configurational disorder of the N-and C-donor of ppyligand in the Cp*Ir III (ppy) complexes.
In the crystal structure there are no solvent molecules of crystallization. Further, any characteristic intermolecular interaction is not observed in this crystal.
When UV light was irradiated to an acetonitrile solution of this complex, a tetrazolato complex, [Cp*Ir(ppy)(MeCN 4 )] (Takayama et al., 2013) was formed, which was confirmed by 1 H NMR spectroscopy.

Experimental
A methanol solution (20 cm 3 ) of NaN 3 (377 mg, 5.18 mmol) was added with stirring to an orange solution of

Refinement
All H atoms were positioned geometrically and refined using a riding model with C-H = 0.95 (for aromatic) or 0.98 Å (for methyl) and with U iso (H) = 1.2 (for aromatic) or 1.5 (for methyl) U eq (C).  The molecular structure of the title compound with atom-numbering scheme. Displacement ellipsoids are drawn at 50% probability level.